Aging causes a reorganization of neuromuscular function such that old vs young adults use more hip and less knee and ankle torque in level and stair gait. PURPOSE We now ask, at what age does this reorganization occur? Since many physiological properties decline rapidly after age 70, we expected the reorganization would not be observed in middle age but in old adults. METHOD Video and GRF data were obtained during level and stair gait from 20 young, 20 middle age and 20 old adults in 5 distinct age groups. Joint torques were computed with inverse dynamics and extensor angular impulse was calculated at each joint. One way ANOVA with 5 age levels was used to identify age group differences with 2 comparisons: 20 vs 60 yr olds and 20, 50 & 60 vs 70 & 80 yr olds. RESULT Hip impulses were not different between 20 and 60 yr olds but were 55% and 66% larger in old vs young and middle age adults in the tasks (both p < .05). Knee impulses were 45% and 21% lower in 60 yr vs 20 yr olds in the tasks (both p < .05). Knee impulses were not different between young and middle age and old adults. Present ankle torque differences were not significant.Table 1: Angular impulse mean (sd) in NmsCONCLUSION Age associated reorganization in neuromuscular function occurs first in the knee extensors and later in hip extensors. Increased hip torque in 70 and 80 yr olds may be a compensatory response to reduced knee torque seen in 60 yr olds. Supported in part by NIH AG16192 grant.